BIGELOW: MEDUSAE FROM THE MALDIVE ISLANDS. 251 



DESCRIPTION OF THE SPECIES. 



I. HYDEOMEDUSAE. 



Dipurena fragilis. 



Dipurena fragilis Mayer, A. G., 1900. Bull. Mus. Comp. Zool, vol. 37, p. 28, 



plate 17. 



This Medusa, if not identical with Dipurena fragilis Mayer, from the Tor- 

 tugas, is very closely allied to it. It appears to diti'er from it in being color- 

 less, and in having the swollen regions on the proboscis much less prominent. 

 The fact that only one specimen was taken makes me hesitate to separate it 

 specifically. 



January 2. Suvadiva atoll, near Dandu island; surface. 



The occurrence of Dipurena in the Indian Ocean is of interest, since this 

 genus has never been taken in the tropical Pacific, though in the tropical 

 Atlantic and Mediterranean it is represented by numerous species. 



Euphysa tetrabrachia, sp. nov. 



Plate 1, Fig. 1. 



I have rather doubtfully referred the present species to Euphysa, to which 

 genus it shows more resemblance than to Corymorpha. The bell is four mm. 

 high by two and one half broad ; pear-shaped, with a low and broad apical 

 projection, and it is perfectly symmetrical. The single long tentacle is well 

 developed, and is about four times as long as the bell is high. The other 

 three, instead of being mere rudiments, are of considerable size, about one 

 third as long as the bell height, and are equally developed. All four are 

 ringed with nettle cells, about three rings on each of the short, and six or 

 eight on the long, tentacle. 



There is an ocellar bulb borne at the base of each tentacle. The proboscis is 

 flask-shaped, its upper portion distended by the swollen half-spherical masses 

 of gonads, arranged in eight fairly distinct rows. The mouth hangs below the 

 bell opening, and bears no lips. 



The bell is colorless and very transparent, the gonads brownish yellow, the 

 proboscis slightly pinkish, and the ocellar bulbs and rings of nettle cells rose 

 pink. 



One .specimen, January 7, in Suvadiva atoll. Surface. 



The generic position of this very distinct species seems doubtful. It agrees 

 with Euphysa in the symmetry of the bell, and in the arrangement of the 

 gonads, which correspond very well to the figures of Euphysa virgulata, given 

 by Alexander Agassiz (North American Acalephae, 1865, p. 190, fig. 317). 



